Diamonds are considered the most famous and valuable jewel in the world. The precious stone for its great value is believed to be the symbol of wealth. Diamonds were made as a result of great volcanic beat and pressure. When a volcano is active, it sometimes explodes and causes great damage to the nearby towns.

    However, at the same time of such a disaster, diamonds were pushed towards the surface of the earth by a number of great volcanic explosions millions of years ago. Thus, it may be very likely to find a diamond after a volcanic eruption. Besides, diamonds are also found among the sand and stones of certain river beds, and in a few places on the floor of the sea, for they were washed down the mountain sides by the rain.

    Diamonds are very rare. There are not many places that produce such precious things in the world. During the last century adventurers from Europe went to Brazil, because they had heard that there were diamonds in the River Amazon. Many of these early diamond miners died of illness or were lost forever in the great forests. But some returned home rich.

    The earliest known diamonds were found in India many centuries ago. The most recent and exciting discoveries have been made in eastern Russia. But most of the world's diamonds now come from the Congo, from Tanzania-which has the largest diamond mine in the world and also from South Africa.

    Are some people born clever, and others born stupid? Or is intelligence developed by our environment and our experience? Strangely enough, the answer to these questions is yes. To some degree our intelligence is given to us at birth, and no amount of education can make a genius out of a child born with low intelligence. On the other hand, a child who lives in a boring environment will develop his intelligence less than one who lives in rich and varied surroundings. Thus the limits of person's intelligence are fixed at birth, whether or not he reaches those limits will depend on his environment. This view, now held by most experts, can be supported in a number of ways.

    It is easy to show that intelligence is to some degree something we are born with. The closer the blood relationship between two people, the closer they are likely to be intelligent. Thus if we take two unrelated people at random from population, it is likely that their degree of intelligence will be completely different. If, on the other hand, we take two identical twins, they will very likely be as intelligent as each other. Relations like brothers and sisters, parents and children, usually have similar intelligence, and this clearly suggests that intelligence depends on birth. Imagine now that we take two identical twins and put them in different environments. We might send one, for example, to a university and the other to a factory where the work is boring. We would soon find differences in intelligence developing, and this indicates that environment as well as birth plays a part. This conclusion is also suggested by the fact that people who live in close contact with each other, but who are not related at all are likely to have similar degree of intelligence.

    Public transport is declining in the rich world. To those who have to squeeze onto the number 25 bus in London, or the A train in New York, the change might not be noticeable. But public transport is becoming less busy in those places, and passenger numbers are flat or falling in almost every American city. That is despite healthy growth in urban populations and employment.

    Although transport agencies blame their unpopularity on things like road works and broken signals, it seems more likely that they are being outcompeted. App-based taxi services like Uber and Lyft are more comfortable and convenient than trains or buses. Cycling is nicer than it was, and rental bikes are more widely available. Cars are cheap to buy, thanks to cut-rate loans, and ever cheaper to run. Online shopping, home working and office-sharing mean more people can avoid travelling altogether.

    The competition is only likely to grow. More than one laboratory is developing new transport technologies and applications. Silicon Valley invented Uber and, more recently, apps that let people rent electric scooters(滑板车) and then abandon them on the pavement. China created sharing-bicycles and battery-powered "e-bikes", both of which are spreading.

    Transport agencies should accept the upstarts, and copy them. Cities tend either to ignore app-based services or to try to push them off the streets. That is understandable, given the rules-are-for-losers attitude of firms like Uber. But it is an error.

    It is doubtful that most people make hard distinctions between public and private transport. They just want to get somewhere, and there is a cost in time, money and comfort. An ideal system would let them move across a city for a single payment, transferring from trains to taxis to bicycles as needed. Building a platform to allow that is hard, and requires much sweet-talking of traditional networks as well as technology firms. It is probably the secret to keeping cities moving.

    Reducing plastic waste isn't easy because the cheap material is found in almost every household item. Now, a delicious and nutritious solution has come up to help reduce our dependence on this environmental hazard.

    David Christian, the co-founder of Evoware, says the idea of creating the biodegradable (生物降解的) products came from concern at the country's high pollution rate. Indonesia is home to four of the world's worst polluted rivers. Since single-use packaging is a large contributor to the problem, Evoware decided to deal with that first.

    After investigating various materials, the company settled on seaweed. Unlike corn, commonly used for biodegradable containers, seaweed does not require resources like water or large amounts of space. Since Indonesian farmers already harvest more seaweed than they can sell, it's easy for the company to find the material.

    Though they will not reveal their production process, Evoware says the seaweed packaging contains no chemicals and is safe to consume. The company has also invented single-use cups, which can break down 30 days after they're thrown away.

    While replacing plastic with the seaweed products may seem appealing to most of us, it is a hard-sell in Indonesia. According to Christian, “The awareness to reduce single-use plastic is still very low. This makes our bioplastic unnecessary.” Also a factor is the cost, which is higher than using plastic. Hopefully, Evoware will succeed in convincing Indonesians and people worldwide that switching to their products will be helpful to protecting our beautiful planet.

    When men get together, they seldom talk about their feelings or inner thoughts. However, they talk about a lot, like their newest computer, how to repair their car, or even business.

    Talk might move to the best place to find fish or women, jump to computer games, then continue to the sport of the season. They also like to tell jokes each other and spend a fair amount of time playing one-up and boasting (吹牛). Men seldom call each other to chat.

    When man meets woman, he usually wants to make a good impression. Many single men try hard to carry on amusing, fun, and pleasant conversations. They use conversation to discover her interests and feelings in order to learn how to be attractive to her.

    Some men, either out of nervousness or ignorance, spend most of the time talking about themselves, often appearing to brag about their achievements or talk endlessly about their problems or work. Even the quietest man talks to his woman when love is new.

    When women get together, they talk about feelings and relationships, their work and their family. They enjoy talking but also want the give and take of talk, then listen. Women often call each other to chat. Conversation is an important part of most women's 1ives.

    As relationships progress, however, many a man turns on the television and forgets how to talk. This raises anger and cry from his woman partner who says, “You never talk to me anymore.” Some men start talking. Many, however, mainly discuss their own achievements and problems.

    When the woman starts talking about her favorite subjects: feelings, family, relationships, friends and her work, many men lose interest or bring the conversation back to themselves. Pretty soon, the man is back to staring at the television each night, wondering where his relationship has gone. The woman is talking to her friends, mom, sister, or neighbor, often about that very relationship and how she is hurting.

An Edinburgh inventor has created a fully biodegradable bottle that is made from paper and a secret combination of plant materials, and it could help save the planet's oceans from plastic pollution and can also be eaten by sea creatures.

The Edinburgh-based Durham University chemistry graduate James Longcroft started a non-profit bottled water company two years ago. He wanted to put all his profits into a charity that provided clean drinking water to countries in Africa.

However, after concerns about the environmental impact of plastic bottles, Mr. Longcroft decided the Edinburgh and London-based company, Choose Water, should go plastic-free. So he came up with a new type of water bottle—a waterproof paper bottle.

"The outside is made from recycled paper, but the inside has to be waterproof, and provides strength so the bottle would keep its structure, and keep the water fresh," Mr. Longcroft said.

When the bottle is thrown in the ocean the degrading process begins within hours leaving the bottle totally degraded (分解)within weeks. The steel cap breaks down within a year.

Mr. Longcroft now believes these novel bottles could revolutionise the industry and says the cost of producing the bottle is around 5 pence more than one made from single-use plastic.

"The main difficulty we face is breaking into a saturated (饱和的)market and competing with an old industry," he said. "Changing an industry will be a big uphill battle, but with the support from the public, we will change the way we look at bottled water."

Researchers warn that eight million tonnes of plastics currently find their way into the ocean every year which will stay in the environment for centuries.

"We really want to get our bottles on shelves and into people's hands as soon as possible—if we can stop even one plastic bottle ending up in the environment it will be worth it," said Mr Longcroft.